1. Field of the Invention
This invention relates to a method for producing an unsaturated carboxylic acid from an alkane using a mixed metal oxide catalyst. In particular, this invention relates to a process for producing acrylic acid from propane by a single step vapor phase oxidation reaction with a mixed molybdovanadate catalyst containing tellurium and antimony.
2. Description of the Prior Art
The commercial production of an unsaturated carboxylic acid, such as acrylic acid or methacrylic acid, is by a catalytic reaction of an olefin, such as propylene or isobutylene, with oxygen to form an alkenylaldehyde, such as acrolein or methacrolein, which is subsequently catalytically reacted with oxygen. Alkanes, such as propane, have advantages of cost and of availability over olefins. Furthermore, a one step process would have advantages over the present commercial process.
There are examples of producing acrylic acid and other unsaturated carboxylic acids from propane and other alkanes in a one step vapor phase catalytic oxidation reaction. U.S. Pat. No. 5,380,933 discloses a catalyst of oxides of molybdenum, vanadium, tellurium, and elements selected from niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, antimony, bismuth, boron, indium or cerium.
U.S. Pat. No. 5,994,580 discloses a process for producing acrylic acid from propane and oxygen using a catalyst containing molybdenum, vanadium, antimony and at least one of niobium, tantalum, tin, tungsten, titanium, nickel, iron, chromium or cobalt.
Japanese published patent application H10-57813 discloses a metal oxide catalyst of molybdenum, vanadium, tellurium and/or antimony and an element selected from niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, bismuth, boron, indium, phosphorus, rare earth elements, alkali metals, alkali-earth metals.
Japanese published patent application H10-45664 discloses a catalyst of oxides of molybdenum, vanadium, antimony and an element selected from niobium, tantalum, tungsten, titanium, zirconium, chromium, iron, manganese, ruthenium, cobalt, rhodium, nickel, palladium, platinum, boron, indium, alkali metals, alkali-earth metals, and rare earth elements.
U.S. Pat. No. 6,746,983 discloses a catalyst to produce unsaturated carboxylic acids by vapor phase oxidation of an alkane or mixture of an alkane and an alkene. The catalyst is a mixed metal oxide of molybdenum, vanadium, one of tellurium, antimony or niobium, one of scandium, yttrium, lanthanum, rhenium, iridium, copper, silver, gold, zinc, gallium, silicon, germanium, arsenic, lead, sulfur, selenium, tin, bismuth, fluorine, chlorine, bromine or iodine. There is no disclosure of a molybdovanadate catalyst containing tellurium, antimony and niobium.
Catalyst with similar compositions have been used for processes other than those for producing acrylic acid and other unsaturated carboxylic acids from propane and other alkanes in a one step vapor phase catalytic oxidation reaction.
U.S. Pat. No. 5,231,214 discloses a process for producing a nitrile from an alkane and ammonia in the presence of a catalyst containing molybdenum, vanadium tellurium, niobium and at least one of magnesium, calcium, strontium, barium, aluminum, gallium, thallium, indium, titanium, zirconium, hafnium, tantalum, chromium, manganese, tungsten, iron, ruthenium, cobalt, rhodium, nickel, palladium, zinc, tin, lead, arsenic, antimony, bismuth, lanthanum or cerium. One example (Example 12) disclosed a catalyst of the composition MoV0.4Te0.2Sb0.1On.
U.S. Pat. No. 5,281,745 discloses a process for producing a nitrile from an alkane and ammonia in the presence of a catalyst containing molybdenum, vanadium, tellurium and at least one of niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, antimony, bismuth, boron or cerium and having a particular X-ray diffraction pattern. One example (Example 4) and a comparative example (Comparative Example 4) disclosed a catalyst of the composition MoV0.4Te0.2Sb0.1On.
U.S. Pat. No. 6,063,728 discloses an ammoxidation catalyst of molybdenum, vanadium, niobium, at least one of tellurium and antimony and optionally at least one of tantalum, tungsten, chromium, titanium, zirconium, bismuth, tin, hafnium, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, silver, zinc, boron, aluminum, gallium, indium, germanium, lead and phosphorus and of a particular X-ray diffraction pattern.
Tellurium can become volatile at the temperatures used for the oxidation of propane to acrylic acid (350–425° C.). Catalyst performance can be affected by the loss of tellurium. In addition, tellurium is an environmental hazard which must be contained or controlled with means which add to the overall process costs.